Paris airports are facing a possible fuel shortage as strike action against pension reform continues.

Workers at all 12 of France's fuel producing refineries are on strike after two plants owned by Exxon Mobil and Petroplus voted to join the protest on Friday, according to a union coordinator at oil company Total SA.

This is not only affecting the supply of fuel to gas stations but also to main airports.

Orly airport (Paris South) is thought to still have fuel reserves to last more than a week, but the main Parisian airport Roissy - Charles de Gaulle might run out of fuel by the end of the weekend.

Flight activity at both airports was unaffected as of Saturday morning, with flights running mostly on time.

Some passengers showed little concern about a possible fuel shortage, and seemed to think a solution would be found before the situation becomes critical.

Saturday is a national demonstration day in France, with millions of people expected to protest against the pension reform in Paris and the main French cities.

French students and labour unions see President Nicolas Sarkozy's pension reform - raising the retirement age from 60 to 62 - as an attack on their well-deserved social protections.

The government says it is the only way to save the money-draining pension system and insists that people have to work longer because they are living longer.

The Education Ministry said 306 high schools were affected to various degrees by strikes on Friday, down from 342 on Thursday. There are around 4,300 high schools in France.

While the protesting students won't reach retirement age for decades, the government is keeping a close eye on their rallies because student protests have brought down major government reforms in the past.

Several French labour unions also announced another round of nationwide demonstrations next Tuesday - in addition to the planned street protests throughout the country expected on Saturday.